Oxygen-capnography mask for continuous CO2 monitoring

ABSTRACT

A face mask for delivering oxygen to, and sampling carbon dioxide exhaled from, a subject includes a partition wall that divides the mask into a subject respiratory space that primarily contains carbon dioxide exhaled by the subject, and an oxygen reservoir space that primarily contain oxygen. The partition wall includes one or two holes to which naris conduits are respectively connected. The naris conduit are positioned in proximity to the subject&#39;s nares to closely obtain carbon dioxide samples. The naris conduits enable oxygen to flow from the oxygen reservoir space to the subject respiratory space during inhalation, while quickly expelling traces of CO2, and they configured such that exhaled CO2 quickly fills them up, during exhalation, and while expelling oxygen traces back to the oxygen reservoir space. During exhalation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Non-Provisional Application claiming priority toU.S. Provisional Patent Application No. 62/373,170, entitled“OXYGEN-CAPNOGRAPHY MASK FOR CONTINUOUS CO₂ MONITORING,” filed Aug. 10,2016, which is herein incorporated in its entirety for all purposes.

FIELD OF THE INVENTION

The present disclosure relates to face masks for delivering oxygen to,and monitoring gases (e.g., carbon dioxide) exhaled from, a patient and,more particularly, to a face mask that impedes dilution of an exhaledgas by a delivered gas, and vice versa.

BACKGROUND

This section is intended to introduce the reader to various aspects ofart that may be related to various aspects of the present techniques,which are described and/or claimed below. This discussion is believed tobe helpful in providing the reader with background information tofacilitate a better understanding of the various aspects of the presentdisclosure. Accordingly, it should be understood that these statementsare to be read in this light, and not as admissions of prior art.

A human respiratory cycle includes a sequence of events during which ahuman inhales and exhales a given volume of air through the respiratorysystem. The respiratory system includes the lungs that, duringbreathing, take in oxygen and expel carbon dioxide, a waste gas. Anexchange of oxygen and carbon dioxide in the lungs can be evaluated, forexample, by measuring oxygen saturation level in the blood andconcentration of exhaled carbon dioxide. After carbon dioxide isexhaled, another respiratory cycle begins with the next breath.

Normal levels of both blood oxygen saturation and concentration ofexhaled carbon dioxide can attest to the healthiness of the respiratorysystem. However, even if one's blood oxygen saturation level is normal,there may still be respiratory dysfunction that may be caused by theinability of body cells to use oxygen that is absorbed in the blood. Ingeneral, the higher the incompetence of body cells to exploit, the lowerthe level of the carbon dioxide produced by these cells and,consequently, the lower the concentration of the carbon dioxide that thesubject exhales.

Face masks for subjects suffering from, prone to, or susceptible tobreathing problems typically include an oxygen port for deliveringoxygen to a subject at a designated rate and a carbon dioxide port forsampling exhaled carbon dioxide. Conventional masks that include the twoports have some drawbacks. One drawback is that the sampled carbondioxide gas is diluted by the oxygen gas flow, which has to be deliveredto the subject continuously. Diluting the carbon dioxide gas by theoxygen (or by any other gas for that matter) decreases. Another drawbackof conventional face masks is that the carbon dioxide sampling port isdistant from the subject's nose and mouth, which may also detrimentallyaffect the carbon dioxide concentration measurement due to, for example,the flow dispersion pattern of the exhaled CO₂. Another drawback ofconventional face masks is that the carbon dioxide sampling port has tostay in a same position relative to the subject's nose and mouth inorder to have a reliable CO₂ concentration measurement. However, thecarbon dioxide sampling port in conventional face masks is prone tomovement due to movement of the subject's head. In addition, positioninga CO₂ sampling port within a stagnation space within the oxygen maskcauses a re-breathing effect where, in some breathing regimens, theconcentration level of the CO₂ near, or at, the sampling port maydeviate from the actual end-tidal values. (In a capnogram, which is aCO₂ waveform displayed by a capnograph, an end-tidal CO₂ (EtCO2) is thepartial pressure of CO₂ at the end of an exhaled breath.). Thesedrawbacks (to name a few) can result in an inaccurate measurement of theconcentration of exhaled carbon dioxide. FIG. 1 illustrates an exampleof a face mask 100 for monitoring exhaled CO₂ while administeringoxygen. Face mask 100 typically includes latex-free soft medical graderesin 110 that makes the mask comfortable for subjects to wear. Mask 100includes a face side 120 and a ‘tubing’ side 130. Tubing side 130includes an oxygen delivering port 140 via which oxygen can beadministered to the mask wearer, and a CO₂ sampling port 150 via whichCO₂ exhaled by the mask wearer can be monitored.

Carbon dioxide sampling port 150 has a longitudinal axis 152. Patient'snose 160 has a longitudinal nostril axis 162. CO₂ sampling port 150 (andalso the adjacent oxygen port 140) is at an acute angle 170 relative tolongitudinal nostril axis 162 such that CO₂ sampling port 150 and oxygenport 140 are placed between the nose (160) and mouth 170 of the patient.In such mask configuration neither CO₂ sampling port 150 nor oxygen port140 is clearly aligned with any of nose 160 or mouth 170.Indiscriminately placing CO₂ sampling port 150 and oxygen port 140 inthe way shown in FIG. 1 results in the drawbacks described above.

A slightly better solution is shown in FIG. 2, which shows a face masksimilar to a face mask that is manufactured by MERCURY MEDICAL, a U.S.company manufacturing airway management devices. Referring to FIG. 2,mask 200 includes a ‘sit’, or ‘knee’, 210 that is oriented (220)approximately at a right angle relative to nostril orientation 230 ofnose 240. Mounting oxygen delivering port 250 and CO₂ sampling port 260on sit/knee 210 of mask 200 better aligns them with nostril orientation230. (CO₂ sampling port 260 has an alignment 270 that forms an acuteangle 280 with nostril orientation 230 that is smaller than acute angle170 in FIG. 1.) However, mask 200 does not really solve the problemsdescribed above since mask 200 has issues similar to those related tomask 100 because CO₂ sampling port 260 is distant from the patient'smouth and nose. Therefore, at least in terms of exhaling carbon dioxide,neither of mask 100 and mask 200 is preferable over the other.

It would be beneficial to have a face mask that minimizes mutualinterference between the two functions—delivering of oxygen to a subjectand sampling of CO₂ exhaled by the subject. It would also be beneficialto have a face mask that is capable of measuring concentration of CO₂with the same efficiency and accuracy independently of whether thesubject breathes through his nose, mouth, or both.

SUMMARY

A summary of certain embodiments disclosed herein is set forth below. Itshould be understood that these aspects are presented merely to providethe reader with a brief summary of these certain embodiments and thatthese aspects are not intended to limit the scope of this disclosure.Indeed, this disclosure may encompass a variety of aspects that may notbe set forth below.

A face mask for delivering oxygen to, and sampling carbon dioxideexhaled from, a subject includes an internal partition wall (“IPW”) thatdivides the mask into a subject respiratory space (“SRS”) that primarilycontains carbon dioxide exhaled by the subject, and a subject oxygenreservoir (“SOR”) space that primarily contains oxygen. The partitionwall includes one or two holes to which naris conduits are respectivelyconnected. The naris conduit(s) is(are) positioned in proximity to thesubject's nares to closely obtain carbon dioxide samples. The narisconduits are configured such that they enable oxygen to flow from theSOR space to the SRS during inhalation while quickly expelling traces ofCO₂, and such that exhaled CO₂ quickly fills up the naris conduitsduring exhalation while expelling oxygen traces back to the SOR. Thus,forming a SRS in the mask prevents dilution of CO₂ during exhalationand, therefore, results in a more accurate measurement of CO₂concentration.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are illustrated by way of example in theaccompanying figures with the intent that these examples not berestrictive. It will be appreciated that for simplicity and clarity ofthe illustration, elements shown in the figures referenced below are notnecessarily drawn to scale. Also, where considered appropriate,reference numerals may be repeated among the figures to indicate like,corresponding or analogous elements. Of the accompanying figures:

FIG. 1 (prior art) shows an oxygen mask provided with a CO₂ samplingport;

FIG. 2 (prior art) illustrates an oxygen/capnography mask which is avariant of the oxygen mask of FIG. 1;

FIG. 3A illustrates an oxygen/capnography mask with an internalpartition wall according to an example embodiment;

FIG. 3B shows the internal partition wall of FIG. 3A;

FIG. 3C shows a naris conduit according to an example embodiment;

FIG. 4A shows an oxygen/capnography mask with small internal partitionwall according to another example embodiment;

FIG. 4B shows the internal partition wall of FIG. 4A;

FIG. 4C illustrates a side-view of mask of FIG. 4A;

FIG. 5A illustrates an oxygen/capnography mask with an internalpartition wall that is laid over the patient's face according to anotherexample embodiment;

FIG. 5B shows the internal partition wall of FIG. 5A;

FIG. 6A illustrates an oxygen/capnography mask with an internalpartition wall according to yet another example embodiment;

FIG. 6B shows the internal partition wall of FIG. 6A;

FIG. 7A illustrates an oxygen/capnography mask with an internalpartition wall according to still another example embodiment;

FIG. 7B shows the internal partition wall of FIG. 7A;

FIG. 8 shows a perforated internal partition with naris conduitsaccording to an example embodiment;

FIG. 9 shows a perforated internal partition without naris conduitsaccording to another example embodiment;

FIG. 10A illustrates an oxygen/capnography mask with an oxygen dispenseraccording to an example embodiment;

FIG. 10B shows the oxygen dispenser of FIG. 10A;

FIG. 11A illustrates an oxygen/capnography mask with an oxygen dispenseraccording to another example embodiment;

FIG. 11B shows the oxygen dispenser of FIG. 11A;

FIG. 12A illustrates an oxygen/capnography mask with an oxygen dispenseraccording to yet another example embodiment;

FIG. 12B shows the oxygen dispenser of FIG. 12A;

FIG. 13A illustrates a naris conduit with a CO₂ sampling port accordingto example embodiments;

FIG. 13B illustrates a naris conduit with a CO₂ sampling port accordingto example embodiments; and

FIG. 13C illustrates a naris conduit with a CO₂ sampling port accordingto example embodiments.

DETAILED DESCRIPTION OF THE INVENTION

One or more specific embodiments of the present disclosure will bedescribed below. These described embodiments are only examples of thepresently disclosed techniques. Additionally, in an effort to provide aconcise description of these embodiments, all features of an actualimplementation may not be described in the specification. It should beappreciated that in the development of any such actual implementation,as in any engineering or design project, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which may vary from one implementation toanother. Moreover, it should be appreciated that such a developmenteffort might be complex and time consuming, but may nevertheless be aroutine undertaking of design, fabrication, and manufacture for those ofordinary skill having the benefit of this disclosure.

The oxygen mask subject of the present disclosure includes a partitionwall for operationally separate between the oxygen delivering functionon the one hand, and the carbon dioxide sampling function on the otherhand. as described in detail below, mask has a mask internal space andis configured to be laid over a face of a subject. The mask has aninternal partition wall that is positioned inside the mask and defines,in the mask internal space, a subject respiration space (SRS) and asubject oxygen reservoir (SOR). In some embodiments, the internalpartition wall may generally include a first naris conduit that extendsfrom the inner partition wall into the SRS and into the SOR, andprovides, through the internal partition wall, a bi-directional fluidflow channel between the SRS and the SOR. (When the mask is laid overthe face of a subject, the first naris conduit is configured to bepositioned in close proximity to the subject nares.) The internalpartition wall may also include a first carbon dioxide conduit whosedistal end is connected to the first naris conduit and is in fluid flowcommunication with an interior space of the first naris conduit. Inother embodiments, the internal partition wall may also include a secondnaris conduit that extends from the inner partition wall into the SRSand into the SOR, and provides, through the internal partition wall, abi-directional fluid flow channel between the SRS and the SOR. (When themask is laid over the face of a subject, the first naris conduit isconfigured to be positioned in close proximity to the subject nares.)The internal partition wall may also include a second carbon dioxideconduit whose distal end is connected to the second naris conduit and isin fluid flow communication with an interior space of the second narisconduit.

FIG. 3A shows a person 300 wearing a domed oxygen/capnography face mask310 on her/his face 302 according to an example embodiment of thepresent invention. Mask 310 includes a dome (convex) shaped side havingan apex 320 and an open side base 322 opposite to apex 320. (The mask'sopen side, or mask's base, 322 is designed to fit snugly onto apatient's face, using a relatively soft seal for example.) Mask 310includes a generally flat ‘oral-nasal’ internal partition wall (IPW)330. (FIG. 3B shows IPW 330 more clearly.) IPW 330, which is positionedinside the domed mask 310 and fully covers the patient's nares andmouth, internally divides mask 310 into two spaces. One main space ofmask 310 is referred to herein as a subject respiration space (SRS). TheSRS is a mask space or cavity defined by or between IPW 330 and themask's base 322 (and/or with subject's face 302) when mask 310 is laidover the subject's face. The other main space of mask 310 is referred toherein as a subject oxygen reservoir (SOR). The SOR is a mask space orcavity defined by or between IPW 330 and mask's apex 320.

Mask 310 may include an oxygen port 340 to deliver oxygen to thepatient, and a CO₂ port 350 to extract samples of the CO₂ exhaled by thepatient. Oxygen port 340, which may be a relatively short tube (e.g.,two centimeters long), may be mounted anywhere on mask 310, providedthat it can fill up the subject oxygen reservoir (SOR) with oxygen,hence the term ‘oxygen reservoir’. Carbon dioxide port 350 is coupled tothe subject respiration space (SRS) via a CO₂ tube 352 and correspondingtubing manifold. Structural constraints related to the location of CO₂port 350 on mask 310 may be more lenient relative to the structuralconstraints related to the location of oxygen port 340 because CO₂ port350 is connected to the naris conduits via a tubing system (e.g., viaCO2 conduits 381 and 383), so positioning of CO₂ port 350 is flexible,as opposed to oxygen port 340 whose positioning affects the mixingdynamics of the two gasses.

Mask 310 may also include an IPW adjustment mechanism to adjust the (andafter the adjustment to maintain the adjusted) spatial location andorientation of IPW 330 in mask 310, so that, when in use, IPW 330 isoperationally maintained at an optimal distance from, and in optimalorientation with respect to, the patient's face in terms of breathingand CO₂ monitoring efficacy. The adjustment mechanism may be connectedto IPW 330 and operable via a user (e.g., physician) through holes inmask 310. By way of example, the gap adjustment mechanism may includethree elongated adjustment rods or shafts 360, 362 and 364. (Othernumbers of adjustment rods or shafts may be used.) Mask 310 may includethree external through holes 361, 363 and 365 through which adjustmentrods or shafts 360, 362 and 364 may respectively be individually andindependently pushed deeper into the mask (that is, pushed forward orcloser to the patient's face), or pulled back (that is, away from thepatient's face). Adjustment rods or shafts 360, 362 and 364 may be setsuch that IPW 330 is maintained at some distance from the face of thepatient so that it does not touch the face.

Through holes 361, 363 and 365 and adjustment rods/shafts 360, 362 and364 may be configured such that the lengthwise position of eachadjustment rod or shaft in the respective through hole in mask 310 ismaintained by a static friction force that exists between the rod orshaft and the hole. The friction force may, nevertheless, enable a user(e.g., physician) to adjust the lengthwise position of each rod or shaftby pushing the rod or shaft into the mask or pulling it back by applyinga force that is large enough to overcome the static friction. Mask 310may also include two pressure relief openings 370 and 372 that enableexhaled air with high CO₂ concentration flow to flow out of the mask dueto slight overpressure that is produced by continues oxygen inflow, tothus prevent building up of excessive pressure inside the mask andrebreathing phenomena when a patient rebreathes part of a previouslyexhaled air with high CO₂ concentration. Of course, any other suitableadjustment mechanism may be used.

One naris conduit 380, or two naris conduits 380 and 382, may be mountedto, or through, IPW 330 and positioned in close proximity to thesubject's nares when the mask is laid over the face of the subject. Anaris conduit (e.g., naris conduit 380) may extend from IPW 330 into theSRS and into the SOR, to provide, through IPW 330, a bi-directionalfluid flow channel between the SRS and the SOR.

Referring to FIG. 3B, IPW 330 may include (e.g., by forming therein)three breathing openings: two ‘nares’ breathing openings (“NBOs”) thatare positioned in close proximity to the patient's nares 384, and amouth breathing opening (“MBO”) 390 that is positioned in closeproximity to the patient's mouth, when mask 310 is laid over the face ofa subject. Two naris conduits (e.g., tubes) 380 and 382 are respectivelymounted to the two NBOs. Each of naris conduits 380 and 382 passesthrough a respective opening in IPW 330 and extends outwardly from IPW330 into the subject respiration space (SRS) and also into the subjectoxygen reservoir (SOR), thus providing a bi-directional fluid flowchannel between the SRS and the SOR, as described herein. Naris conduits380 and 382 are ‘breathing conduits’ because they are used for bothdelivering oxygen to the patient and releasing (for extracting samplesof) the CO₂ that the patient exhales. The way naris conduits 380 and 382function is described in more detail below, for example in connectionwith FIG. 3C. MBO 390 provides a passage between the SOR and the SRS, sothat oxygen may freely pass from the SOR to the SRS. During exhalationthrough the mouth, a CO₂ conduit 392 may be used to extract CO₂ samples.Carbon dioxide conduit 392, which may be positioned in a region near themouth, is in fluid flow communication with the SRS.

A CO₂ extraction tubing system (“ETS”) is attached to IPW 330 in orderto monitor CO₂ that is exhaled from the patient's nares and mouth.Depending on the number of naris conduits that the IPW includes (onenaris conduit; e.g., naris conduit 380, or two naris conduits; e.g.,naris conduits 380 and 382), the CO₂ ETS may respectively include afirst CO₂ conduit (e.g., CO₂ conduit 381) and a second CO₂ conduit(e.g., CO₂ conduit 383). A distal end of each CO₂ conduit is connectedto a respective naris conduit such that it is in fluid flowcommunication with an interior space of that naris conduit. The distalend of the first CO₂ conduit (e.g., CO₂ conduit 381) may be positionedin close proximity to a first naris (one of patient's nares 384, FIG.3B), and the distal end of the second CO₂ conduit (e.g., CO₂ conduit383) may be positioned in close proximity to a second naris (the othernaris of nares 384). In some other embodiments, the CO₂ ETS may alsoinclude CO₂ conduit 392 that has a distal end that is positioned inproximity to the patient's mouth (and in fluid flow communication withthe SRS.) Each of CO₂ conduits 381, 382 and 392 has a proximal end thatmay be connected to a common CO₂ conduit 352 via a tubing manifold.(Carbon dioxide conduit 381, CO₂ conduit 383 and CO₂ conduit 392 may beconnected to the CO₂ port 350 via common conduit 352).

During use of mask 310, oxygen is constantly provided to mask 310 viaoxygen port 340, and oxygen constantly fills up the SOR space insidemask 310, ready to be inhaled by the patient. During inhalation, oxygenis delivered to the patient through naris conduits 380 and 382, and alsothrough mouth breathing opening (MBO) 390. Most of the oxygen that iscontained in mask 310 is contained in the oxygen reservoir part of themask (in the SOR space), and it is readily available for the patientduring inhalation. When the patient exhales CO₂ (CO₂ enriched air), theexhaled CO₂ quickly supersedes/displaces oxygen in the SRS part of mask310, and, in particular, the oxygen in nares conduits 380 and 382, andthe oxygen adjacent to the CO₂ conduit 392. Since the volume of thespaces in nares conduits 380 and 382 and around the patient's mouth arerelatively small (e.g., relative to an amount of oxygen and CO₂ exchangeduring one breath cycle), the exhaled CO₂ supersedes most, if not all,of the oxygen in these spaces quickly, thus preventing dilution of CO₂and enabling a more reliable sampling of the exhaled CO₂, and,therefore, a more reliable measurement of the concentration level ofCO₂.

Referring to FIG. 3C, reference numeral 330′ is a symbolicrepresentation of inner partition wall (IPW) 330 that separates betweenthe SRS space and the SOR space. The description of naris conduit 380also applies to naris conduit 382 (with CO₂ conduit 381 replaced withCO₂ conduit 383), as each of naris conduit 380 and naris conduit 382 isprimarily intended for a different naris of the patient. ‘A narisconduit primarily intended for a particular naris’ means that aparticular naris conduit; e.g., naris conduit 380, may deliver moreoxygen to the ‘intended’ naris, which is the naris adjacent to thatnaris conduit, though some of the oxygen that pass through theparticular naris conduit may reach the other naris, and, similarly, mostof the CO₂ exhaled from a particular naris reaches the ‘intended’ narisconduit, which is the adjacent naris conduit, though some CO₂ may reachthe other naris conduit.)

Naris conduit 380 is substantially perpendicular to, and extendsoutwardly from both sides of, IPW 330′ (that is, from it extends fromthe ‘SRS’ side of IPW 330′ into the SRS space, and from the ‘SOR’ sideof IPW 330′ into the SOR space), and thus naris conduit 380 provides abi-directional fluid flow channel between the SRS and the SOR spaces.Naris conduit 380 includes a CO₂ extraction hole 384 to which CO₂conduit 381 is fixedly mounted. The distal end of conduit 381 may bealigned with the surface of naris conduit 380 or protrude into internalspace 385 of naris conduit 380, and be in fluid flow communication withinternal space 385 of naris conduit 380.

Naris conduit 380 has a length L and an internal diameter D. Carbondioxide conduit 381, which is fixedly connected to naris conduit 380,has a diameter d (d<D), as shown in FIG. 3C. The values of L and D, andthe ratio R=d/D, may be optimized in terms of fluid dynamics accordingto expected breathing characteristics (e.g., breathing cycle, breathingefficacy, etc.) of patients, and also in terms of re-breathing effect(e.g., minimizing this effect). For example, the values of L, D and Rmay be set such that, during a breathing-in phase of a breathing cycle,CO₂ traces from the previous exhalation phase are quickly expelled(evacuated) from space 385 inside naris conduit 380 through conduit 381,and, space 385 is quickly filled up with oxygen so that oxygen (oroxygen-enriched air) is readily available to the patient duringinhalation. In addition, the values of L, D and R may be set such that,during a breathing-out phase of the breathing cycle, the CO₂ exhalationdynamics (e.g., CO₂ pressure and flow rate) can quickly clear space 385from oxygen (e.g., by expelling the oxygen from naris conduit 380 backinto the SOR) and fill up space 385 with CO₂. (By ‘quickly’ is meantbefore the relevant breathing phase ends.) The effect of theoptimization of the values of L, D and R is that during inhalation, thepatient inhales only, or mostly, oxygen or oxygen-enriched air, andduring exhalation the CO₂ sampling system receives CO₂ with genuineconcentration level. In other words, the better the optimization of thevalues of L, D and R, the lesser the amount of oxygen that dilutes CO₂samples during exhalation, and the lesser the amount of CO₂ in theinhaled oxygen. (When the values of L, D and R are optimized, the amountof oxygen diluting the CO₂ sample is negligible.)

During inhalation of oxygen, the subject, by breathing in, creates asub-atmospheric pressure that draws from the oxygen reservoir (SOR) intothe patient's respiratory space (SRS), and ultimately into the subject'slungs, only the amount of oxygen that is required for breathing, whilethe remainder of the oxygen contained in the SOR is held in reserve (andpartially flows out of mask 310 through pressure relief openings 370 and372), ready for use during subsequent inhalations.

By creating two, separate, spaces by partition wall 330—one space whichis the subject respiratory space, and another space which primarilycontains oxygen—and manipulating the exchange of oxygen and CO₂ in thenares conduits 380 and 382, and near mouth opening 390, the oxygeninhaled by a patient is not diluted, or only negligibly diluted, by theexhaled CO₂, and the CO₂ exhaled by the patient is not diluted, or onlynegligibly diluted, by oxygen at least in those (‘interference-free’)spaces from which CO₂ conduit 381, 383 and 392 extract CO₂. Becausepartition wall 330 is large enough to cover the subject's airways (noseand mouth) and CO₂ is sampled directly from the subject's airways, theconcentration level of the CO₂ exhaled from the subject's airways (andpasses through CO₂ conduit 381, 383 and 392, and finally through CO₂sampling port 350) remains substantially the same even when the maskslightly moves on the subject's face. In addition, since the CO₂ conduit381, 383 and 392 cover the subject's two nostrils and mouth, andpartition wall 330 is large, partition wall 330 averages the CO₂ exhaledby the various patient's airways. Therefore, an issue that may exist inother types of oxygen masks, regarding whether a patient breathes onlythrough the nose (through one naris or through both nares) or onlythrough the mouth, is non-existent in mask 310 or in its variants.

FIG. 4A shows an oxygen/capnography mask 410 with an internal partitionwall (IPW) 430 worn on a subject 400 according to another exampleembodiment of the present invention. IPW 430, which is positioned insidethe domed mask, is smaller than IPW 330 of FIGS. 3A-3B and is positionedin proximity to the patient's nares. (While IPW 330 fully covers thepatient's nares and mouth (and, therefore, IPW 330 includes an extrabreathing opening 390 for the patient's mouth, IPW 430 does not includea mouth breathing opening.) IPW 430 is kept at distance from thepatient's face by using an adjustment mechanism that includes, in thisexample, adjustment rod or shaft 460, 462 and 466. In this embodiment,IPW 430 is smaller than IPW 330 and partly covers the nares and mouth ofthe patient.

IPW 430 includes two naris breathing openings to which two narisconduits 480 and 482 are respectively connected in a similar way asshown in FIGS. 3A-3B. To naris conduits 480 and 482 are respectivelyconnected CO₂ conduit 481 and CO₂ conduit 483 that function and areoptimized in a similar way as CO₂ conduit 381 and CO₂ conduit 383 ofFIGS. 3A-3C.

A carbon dioxide conduit 492 is positioned near, or in close proximityto, the patient's mouth and functions in a similar way as CO₂ conduit392 of FIGS. 3A-3B. CO₂ conduits 481 and 482 are positioned adjacent, orin close proximity, to the patient's nares and function in a similar wayas CO₂ conduits 381 and 382 of FIGS. 3A-3B. Carbon dioxide conduits 481,482 and 492 have a proximal end, and the proximal ends of the threeconduits may be connected to a common CO₂ conduit 452 via a tubingmanifold. Mask 410 may also include: (1) an oxygen port 440 to deliveroxygen to the subject oxygen reservoir (SOR) space insideoxygen/capnography mask 410, and (2) a CO₂ sampling port 450 that isconnected to CO₂ conduit 452 through which exhaled carbon dioxide may beextracted by a CO₂ sampling system. (FIG. 4B shows IPW 430 and itstubing system more clearly.)

FIG. 4C shows a schematic view of mask 410 of FIG. 4A. Mask 410′includes a flat IPW 430′ that is roughly or approximately “L” shaped.One ‘leg’ (leg 420) of L-shaped IPW 430′ is positioned in proximity tothe patient's nares, so it includes two naris conduits (naris conduits480′ and 482′) to which CO₂ conduits 481 and 483 are respectivelyconnected in order to obtain therefrom CO₂ samples from the CO₂ that isexhaled from the patient's nose. The other leg (leg 422) of L-shaped IPW430′ is positioned in proximity to the patient's mouth, so it includes athrough hole to which CO₂ conduit 492 is connected in order to obtainCO₂ samples exhaled from the patient's mouth. IPW 430 (and IPW 430′) hassimilar benefits as IPW 330 and is subjected to similar optimization itterms of dimensions. An angle α between the legs 420 and 422 of IPW 430′may be subjected to optimization in terms of separation between oxygenand CO₂ during breathing. An elongated conduit fixation member 460 maybe connected to IPW 430′ (e.g., to leg 422), on the one hand, and toconduit 452′, on the other hand, and keep the CCO₂ 2 tubing, as a whole,in place inside the mask. Also shown in FIG. 4C are oxygen port 440′,CO₂ port 450′ and a CO₂ conduit that collects CO₂ samples from CO₂conduits 481′, 483′ and 492′.

FIG. 5A shows an oxygen/capnography mask 510 with an internal partitionwall (IPW) 530 worn on a subject 500 according to another exampleembodiment. IPW 530, which is positioned inside the domed mask, issimilar to IPW 330 in the sense that it also includes two includes twonaris conduits 580 and 582 and a mouth breathing opening. IPW 530differs from IPW 330 in that IPW 530 is somewhat larger than IPW 330 andincludes a perimeter 520 that is adapted to tightly fit onto, and touch,the face of the patient. IPW 530 may be regarded as a small mask insidemask 510. FIG. 5B shows IPW 530 and the CO₂ tubing more clearly. IPW 530is larger than IPW 330 and covers the nose tip and the mouth of thepatent.

FIG. 6A shows an oxygen/capnography mask 610 with an internal partitionwall (IPW) 630 according to another example embodiment. IPW 630 is verysmall relative to IPWs 330, 430 and 530, and is positioned near thenares of the patient. IPW 630, which is positioned inside the domedmask, has a size that complies with the width of the nares; that is, IPW630 may have a size that is similar to (e.g., somewhat smaller than, orsomewhat larger than) the width of the subject's nose. (The size of anIPW can be reduced to any size that still imparts it the functionalitiesand benefits described herein.) IPW 630 may be shaped like a scoop inorder to more efficiently capture CO₂ from the patient's nares in aregion where the CO₂ cannot be washed away by oxygen. (The patient maybreathe normally via the mouth without affecting, or be effected by, thebreathing and CO₂ monitoring via IPW 630.) By way of example, IPW 630includes at least one naris conduit, which is shown at 680. (Narisconduit 680 is similar to, and functions in a similar way as, narisconduits 380, 480 and 580. Naris conduit 680 may also be subjected to asimilar optimization calculation.) IPW 630 may be positioned in a regionbetween the patient's upper lip and nose, and naris conduit 680 may becentered between the two nares in order to capture CO₂ that is exhaledfrom both nares. A CO₂ conduit 620 is connected between a through holein naris conduit 680 and a CO₂ port 650 so that CO₂ can be extractedfrom naris conduit 680 and delivered to a CO₂ monitoring system via CO₂port 650. IPW 630 is kept at distance from the patient's face by usingan adjustment mechanism that includes, in this example, adjustment rodor shaft 660, 662 and 666. (FIG. 6B shows IPW 630 more clearly.)

IPW 630 may be made of a flat thin plastic material whose surface has anarea that is small but large enough to produce, during exhalation, adynamic CO₂ pressure that is high enough to expel oxygen from the regionbetween the patient's nose and mouth, leaving there only, or mostly, CO₂from which CO₂ samples can be extracted through CO₂ conduit 620.

FIG. 7A shows an oxygen/capnography mask 710 with an internal partitionwall (IPW) 730 according to another example embodiment. IPW 730, whichis positioned inside the domed mask, is similar to IPW 630 in terms ofsize. (IPW 730 is also very small relative to IPWs 330, 430 and 530, andis positioned near the nares of the patient.) IPW 730 differs from IPW630 in that IPW 730 does not include naris conduits. Instead, two CO₂conduits 781 and 783 are connected to CO₂ extracting openings in IPW 730and function in a similar way as CO₂ conduits 381 and 383 of FIGS.3A-3C.

IPW 730 may be shaped like a scoop in order to more efficiently captureCO₂ from the patient's nares in a region where the CO₂ cannot be washedaway by oxygen. (The patient may breathe normally via the mouth withoutaffecting, or be effected by, the breathing and CO₂ monitoring via IPW730.) IPW 730 may be positioned in a region between the patient's upperlip and nose, and the openings in IPW 730, to which the distal ends ofCO₂ conduits 781 and 783 are connected, may respectively be positionedin front of the two nares in order to capture CO₂ that is exhaled fromthem. The proximal ends of CO₂ conduits 781 and 783 may be connected toa CO₂ conduit 752 whose other end is connected to a CO₂ port 750 so thatCO₂ can be extracted from IPW 730 and delivered to a CO₂ monitoringsystem via CO₂ port 750. IPW 730 is kept at distance from the patient'sface by using an adjustment mechanism that includes, in this example,adjustment rod or shaft 760, 762 and 766. (FIG. 7B shows IPW 730 moreclearly.)

IPW 730 may be made of a flat thin plastic material whose surface has anarea that is small but large enough to produce, during exhalation, adynamic CO₂ pressure that is high enough to expel oxygen from the regionbetween the patient's nose and mouth, leaving there only, or mostly, CO₂from which CO₂ samples can be extracted through CO₂ conduit 752.

FIG. 8 shows an inner partition wall (IPW) 830 according to anotherexample embodiment. IPW 830 is similar to IPW 330 with the exceptionthat IPW 830 is perforated, with the perforation slits or holes shown at884. IPW 330 includes two naris conduits (880 and 882), a mouthbreathing opening 890, and CO₂ tubing that includes three CO₂ conduits(881, 883 and 892) that are connected to a common CO₂ conduit 852.

IPW 830 differs from IPW 330 in that it contains perforation slits orholes. (Some of the perforation slits or holes are shown at 884, thoughall of the perforation slits or holes in IPW 830 are referenced byreference numeral 884.) Using perforation slits or holes such as, orsimilar to, perforation slits or holes 884, is beneficial because suchperforation may prevent under-pressure condition in the subjectrespiration space (SRS) during inhalation and over-pressure condition inthe SRS during exhalation, and thus facilitates breathing when a patienthas breathing difficulties such as breathing in oxygen. Perforationslits or holes 884 also reduce the re-breathing effect, which is abreathing condition in which the patient breathes in CO₂ that is nottimely washed away (from the SRS part of the mask) before inhalingoxygen. The size and arrangement (e.g., location, density) ofperforation slits or holes 884 may be manipulated in order to optimizeIPW 830 in terms of, for example, ease of breathing, re-breathingeffect, and CO₂ sampling efficacy. For example, the closer theperforation slits or holes to a CO₂ ‘sampling point’ (e.g., narisconduit 880 or 882) in the IPW, the denser the perforation slits/holes.In another example, the closer the perforation slits or holes to the CO₂sampling point in the IPW, the smaller the slits/holes (e.g., thesmaller their diameter). By way of example, perforation slits or holes884 are evenly distributed in IPW 830, and all slits/holes have asimilar size.

FIG. 9 shows an inner partition wall (IPW) 930 according to anotherexample embodiment. IPW 930 is similar to IPW 830 in the sense that it,too, includes three CO₂ conduits (conduits 981, 983 and 992) andperforation slits or holes (some of which are shown at 982, thoughreference numeral 982 refers to all perforation slits or holes in IPW930). However, IPW 930 differs from IPW 830 in that IPW 930 does notinclude a mouth breathing opening and naris conduits. Instead, multipleperforation slits or holes, for example perforation slits or holes 920,are used instead of one large mouth breathing opening, and, in addition,CO₂ conduits 981, 983 and 992 are respectively directly connected to IPW930 via CO₂ sampling, or access, points in IPW 930, where the CO₂sampling, or access, points in the IPW may be perforation slits orholes; e.g., perforation slits or holes 981′, 983′ and 992′.

The size and arrangement (e.g., location, density) of the perforationslits or holes 982 may be manipulated in order to optimize functionalityof IPW 930 in terms of ease of breathing, the re-breathing effect, andCO₂ sampling efficacy. For example, the closer the perforation slits orholes to a CO₂ sampling, or access, point (e.g., CO₂ sampling point981′), the denser the slits/holes. In another example, the closer theslits or holes to a CO₂ sampling point (e.g., CO₂ sampling point 983′),the smaller the slits/holes (e.g., the smaller their diameter). By wayof example, perforation slits or holes 982 are evenly distributed in IPW930, and all slits/holes have a similar size. A CO₂ sampling point maybe, for example, a naris conduit (e.g., naris conduit 880 or 882), as inFIG. 8, or, in the absence of a naris conduit, a perforation slit orhole (e.g., perforation slits or holes 981′, 983′, 992′), as shown inFIG. 9.

FIG. 10A shows an oxygen/capnography mask 1010 according to anotherexample embodiment. Mask 1010 may include an IPW 1030 that may besimilar to IPW 630. Mask 1010 includes an oxygen port 1040. Distal end1042 of oxygen port 1040, which resides in mask 1010, may include a gasdisperser 1020 (e.g., sprinkler, scatterer, sprayer, etc.) fordispersing (e.g., by spraying) oxygen into the oxygen reservoir part ofmask 1010, which is most of the space inside mask 1010. Spraying oxygeninto mask 1010 has a benefit over transferring it in the form of gas jet(as is the case with oxygen port 340 in FIG. 3A, for example) because anoxygen jet causes turbulences inside the mask (e.g., mask 310, FIG. 3A),and turbulences inside the mask detrimentally affect (e.g., disrupt)oxygen inhalation and CO₂ sampling (because turbulences mix up the twogasses). Gas disperser 1020 is shown more clearly in FIG. 10B, which isdescribed below. Referring to FIG. 10B, gas disperser 1020 may include,at its distal end 1042, a hollow base part 1070 on top of which ismounted a hollow pointed, or tapering, member 1050 having an angle β(e.g., β=30 degrees). Pointed or tapered member 1050 may have aplurality of gas outlets, or vents, 1060 for dispersing oxygen (that is,through which oxygen can be dispersed; e.g., sprayed out) into theoxygen reservoir space of mask 1010. The gas dispenser at the distal endof an oxygen port may be or include a pointed cap that is fixedly keptat distance from a hollow base. Such structure results in ‘peripheral’dispersion of oxygen through an opening formed by the distance betweenthe cap and the hollow base. FIGS. 11A-11B and 12A-12B, which aredescribe below, show example pointed cap like gas dispensers. (A gasdispenser may include another cap or a cap similar to the cap shown inFIGS. 11A-11B and 12A-12B.)

FIG. 11A shows an oxygen/capnography mask 1110 according to anotherexample embodiment. Mask 1110 may include an IPW 1130 that may besimilar to IPW 630. Mask 1110 includes an oxygen port 1140. A distal end1142 of oxygen port 1140, which resides in mask 1110, may include adisperser 1120 for dispersing oxygen in the oxygen reservoir part ofmask 1110, which, in this embodiment, may occupy most of the spaceinside mask 1110. Distributing oxygen into mask 1010 in the waydescribed below has a benefit over transferring oxygen in the form ofgas jet (as is the case with oxygen port 340 in FIG. 3A, for example)because an oxygen jet causes turbulences inside the mask (e.g., mask310, FIG. 3A), which has drawbacks as described above in connection withFIGS. 10A-10B.

Gas disperser 1120 is shown more clearly in FIG. 11B, which is describedbelow. Referring to FIG. 11B, gas disperser 1120 may include, at itsdistal end 1142, a hollow base part 1180 on top of which, thoughdistanced from base part 1180, is mounted a pointed, tapering orconical, cap 1150 having an angle γ (e.g., γ=120 degrees). Pointed cap1150 is fixedly distanced from base part 1180 by elongated spacingmembers 1170, 1172 and 1174. The distance between the base of pointedcap 1150 and the base member 1180 results in a gas outlet, or vent, 1160through which oxygen flows out into the subject oxygen reservoir (SOR)space of mask 1110 in the form of a gas ‘cloud’.

FIG. 12A shows an oxygen/capnography mask 1210 according to anotherexample embodiment. Mask 1210 may include an IPW 1230 that may besimilar to IPW 1130. Mask 1210 includes an oxygen port 1240. Distal end1242 of oxygen port 1240, which resides in mask 1210, may include a gasdisperser 1220 for distributing oxygen in the oxygen reservoir part ofmask 1210, which is most of the space inside mask 1210.

Gas disperser 1220 is shown more clearly in FIG. 12B, which is describedbelow. Referring to FIG. 12B, gas disperser 1220 may include, at itsdistal end 1242, a hollow base part 1230 on top of which, thoughdistanced from base part 1230, is mounted a pointed cap 1250 that issimilar to pointed cap 1150 of FIGS. 11A-11B, except that pointed cap1250 is mounted on base part 1230 with the cap's apex 1252 turning to,or facing, the opposite direction; that is, towards base part 1230.Pointed cap 1250 is fixedly kept at distance from base part 1230 byelongated spacing members similar to those that keep pointed cap 1150 atdistance from base part 1130. The distance between the base of pointedcap 1250 and the base member 1230 results in a gas outlet, or vent, 1260through which oxygen flows out into the SOR space of mask 1210 in theform of a gas ‘cloud’. FIGS. 10A-10B, 11A-11B and 12A-12B show someexample gas dispersers. Alternative (e.g., other or similar) types ofgas dispensers may be used.

FIGS. 13A-13C show various structures of naris conduits according toexample embodiments. Referring to FIG. 13A, a naris conduit 1310includes a longitudinal axis 1320 and is attached to or mounted on anIPW (the IPW is shown symbolically at 1330) such that IPW 1330 defines,or separates between, a subject respiration space (SRS) and a subjectoxygen reservoir (SOR). Naris conduit 1310 (or its longitudinal axis1320) may be perpendicular to IPW 1330, or it may be at an angle withrespect to IPW 1330. Naris conduit 1310 also includes a CO₂ conduit1340. Carbon dioxide conduit 1340 may be a short, straight, tube that ismounted on, and protrudes only outwardly from, body 1350 of narisconduit 1310. Carbon dioxide conduit 1340 may protrude from body 1350 ofnaris conduit 1310 perpendicularly. Carbon dioxide conduit 1340 includesan open channel that is in fluid flow communication with inner space1360 of naris conduit 1310. During inhalation, oxygen fills up narisconduit 1310 with oxygen while oxygen is transferred (1370) throughnaris conduit 1310 from the SOR side to the SRS side. During exhalation,CO₂ exhaled by the patient forcedly expels oxygen from the interiorspace 1360 of naris conduit 1310 back into the SOR side, and some of theexhaled CO₂ (the CO₂ samples) are extracted (1380) through CO₂ conduit1340 (and through a connecting tube) by a CO₂ monitoring system.

Referring to FIG. 13B, naris conduit 1312 is structurally similar tonaris conduit 1310 except for the CO₂ conduit: the CO₂ conduit of(connected to) naris conduit of 1312 protrudes from body 1352 of narisconduit 1312 both outwardly (the part protruding outwardly is shown at1390) and inwardly (into internal space 1362 of naris conduit 1312; thepart protruding inwardly is shown at 1392). Distal end 1313 of the CO₂conduit may reach, or be aligned with (e.g., coincide with),longitudinal axis 1322 of naris conduit 1312, or it may be shorter suchthat it is misaligned with longitudinal axis 1322.

Referring to FIG. 13C, naris conduit 1314 is structurally similar tonaris conduits 1310 and 1312 except for the CO₂ conduit: like in FIG.13B, CO₂ conduit 1315 of naris conduit of 1314 protrudes from body 1354of naris conduit 1314 both outwardly, as shown at 1394, and inwardly(into internal space 1364 of naris conduit of 1314), as shown at 1396.However, CO₂ conduit 1315 is an “L” shaped tube having two tube sectionsor legs: one tube section or leg (an ‘outlet’ part, shown at 1394 and1396) that is mounted on body 1354 and transfer CO₂ samples to a CO₂monitoring system, and another tube section or leg (an ‘inlet’ part,shown at 1317) that is directed towards (it faces) the SRS side in orderto collect CO₂ samples. Tube section 1317 may be parallel to (e.g.,coincide with) longitudinal axis 1324 of naris conduit 1314, or it mayslant with respect to longitudinal axis 1324 of naris conduit 1314.

Various aspects of the techniques disclosed herein are combinable withvarious types of binary-gas or multi-gas face masks. Although thediscussion herein relates to face masks for delivering oxygen andsampling exhaled carbon dioxide gases, the techniques are not limited inthis regard.

While certain features have been illustrated and described herein, manymodifications, substitutions, changes, and equivalents will now occur tothose of ordinary skill in the art, and the appended claims are intendedto cover all such modifications and changes.

The invention claimed is:
 1. An oxygen-capnography face mask comprising:a mask having a mask internal space and configured to be laid over aface of a subject; an inner partition wall positioned in the maskinternal space and defining, in the mask internal space, a subjectrespiration space and a subject oxygen reservoir, the internal partitionwall comprising: a first naris conduit, the first naris conduitextending from the inner partition wall into the subject respirationspace and into the subject oxygen reservoir and providing, through theinner partition wall, a bi-directional fluid flow channel between thesubject respiration space and the subject oxygen reservoir, wherein whenthe mask is laid over the face of a subject, the first naris conduit isconfigured to be positioned in close proximity to the subject nares; anda first carbon dioxide conduit having a distal end that is connected tothe first naris conduit and is in fluid flow communication with aninterior space of the first naris conduit.
 2. The face mask as in claim1, wherein the inner partition wall comprises: a second naris conduit,the second naris conduit extending from the inner partition wall intothe subject respiration space and into the subject oxygen reservoir andproviding, through the internal partition wall, a bi-directional fluidflow channel between the subject respiration space and the subjectoxygen reservoir, wherein when the mask is laid over the face of asubject, the second naris conduit is configured to be positioned inclose proximity to the subject nares; and a second carbon dioxideconduit having a distal end that is connected to the second narisconduit and is in fluid flow communication with an interior space of thesecond naris conduit.
 3. The face mask as in claim 2, wherein, when themask is laid over the face of the subject, the first naris conduit ispositioned in proximity to one naris and the second naris conduit ispositioned in proximity to the other naris.
 4. The face mask as in claim2, comprising: a mouth breathing opening formed in inner partition wall,the mouth breathing opening positioned in close proximity to thesubject's mouth when the mask is laid over the face of the subject; anda third carbon dioxide conduit, the third carbon dioxide conduit havinga distal end that is positioned in a region near the mouth and is influid flow communication with the subject respiration space.
 5. The facemask as in claim 4, comprising a carbon dioxide port, wherein the firstcarbon dioxide conduit, the second carbon dioxide conduit and the thirdcarbon dioxide conduit are connected to the carbon dioxide port.
 6. Theface mask as in claim 4, wherein the inner partition wall covers thefirst naris, the second naris and the mouth of the subject.
 7. The facemask as in claim 4, wherein the inner partition wall partly covers thefirst naris, the second naris and the mouth of the subject.
 8. The facemask as in claim 1, wherein the inner partition wall is “L” shaped. 9.The face mask as in claim 1, wherein the inner partition wall covers thenose tip and the mouth of the subject.
 10. The face mask as in claim 1,wherein the inner partition wall has a width approximately the width ofthe nares.
 11. The face mask as in claim 1, wherein the inner partitionwall is perforated by a plurality of holes.
 12. The face mask as inclaim 1, wherein the first carbon dioxide conduit protrudes outwardlyfrom the first naris conduit.
 13. The face mask as in claim 1, whereinthe first carbon dioxide conduit protrudes both outwardly from andinwardly into the first naris conduit.
 14. The face mask as in claim 13,wherein the first carbon dioxide conduit protruding inwardly into thefirst naris conduit comprises a tube leg that is perpendicular to alongitudinal axis of the first naris conduit, and a tube leg that isparallel to, or coincides with, the longitudinal axis of the first narisconduit.
 15. The face mask as in claim 1, comprising: an oxygen port,said oxygen port having a distal end residing in the face mask; and agas disperser mounted on the distal end of the oxygen port, to disperseoxygen into the subject oxygen reservoir.
 16. The face mask as in claim15, wherein the gas disperser comprises: a tapered member comprising aplurality of gas outlets for dispersing oxygen.
 17. The face mask as inclaim 15, wherein the gas disperser comprises: a hollow base; and a cap,the cap being fixedly kept at distance from the hollow base.
 18. Anoxygen-capnography face mask comprising: a mask having a mask internalspace and configured to be laid over a face of a subject; an innerpartition wall positioned in the mask internal space and defining, inthe mask internal space, a subject respiration space and a subjectoxygen reservoir, wherein the inner partition wall is perforated by aplurality of holes and wherein the size and arrangement of theperforation holes are optimized in terms of ease of breathing,re-breathing effect, and carbon dioxide sampling efficacy, the innerpartition wall comprising: a first naris conduit, the first narisconduit extending from the inner partition wall into the subjectrespiration space and into the subject oxygen reservoir and providing,through the inner partition wall, a bi-directional fluid flow channelbetween the subject respiration space and the subject oxygen reservoir,wherein when the mask is laid over the face of a subject, the firstnaris conduit is configured to be positioned in close proximity to thesubject nares, and a first carbon dioxide conduit having a distal endthat is connected to the first naris conduit and is in fluid flowcommunication with an interior space of the first naris conduit.
 19. Anoxygen-capnography face mask comprising: a mask having a mask internalspace and configured to be laid over a face of a subject; an innerpartition wall positioned in the mask internal space and defining, inthe mask internal space, a subject respiration space and a subjectoxygen reservoir, wherein the inner partition wall is perforated by aplurality of holes, the inner partition wall comprising: a first narisconduit, the first naris conduit extending from the inner partition wallinto the subject respiration space and into the subject oxygen reservoirand providing, through the inner partition wall, a bi-directional fluidflow channel between the subject respiration space and the subjectoxygen reservoir, wherein when the mask is laid over the face of asubject, the first naris conduit is configured to be positioned in closeproximity to the subject nares and wherein the closer the holes to thefirst naris conduit or to the second naris conduit, the denser theholes; and a first carbon dioxide conduit having a distal end that isconnected to the first naris conduit and is in fluid flow communicationwith an interior space of the first naris conduit.
 20. Anoxygen-capnography face mask comprising: a mask having a mask internalspace and configured to be laid over a face of a subject; an innerpartition wall positioned in the mask internal space and defining, inthe mask internal space, a subject respiration space and a subjectoxygen reservoir, wherein the inner partition wall is perforated by aplurality of holes, the inner partition wall comprising: a first narisconduit, the first naris conduit extending from the inner partition wallinto the subject respiration space and into the subject oxygen reservoirand providing, through the inner partition wall, a bi-directional fluidflow channel between the subject respiration space and the subjectoxygen reservoir, wherein when the mask is laid over the face of asubject, the first naris conduit is configured to be positioned in closeproximity to the subject nares and wherein the closer the holes to thefirst naris conduit or to the second naris conduit, the smaller theholes; and a first carbon dioxide conduit having a distal end that isconnected to the first naris conduit and is in fluid flow communicationwith an interior space of the first naris conduit.